Numbers from 11 to 99.
11: Jyuu-ichi
Since 11 = 10 + 1, you can simply read the numbers in the equation without “+”.
10(Jyuu) and 1(Ichi), meaning Jyuu-ichi.
In the same way, 12 is Jyuu-ni, 13 is Jyuu-san, and 14 is Jyuu-yon
Then, how about 21?
Since 21 = 2 x 10 + 1, you can also simply read the numbers in the equation without “x” and “+”.
2(Ni), 10(jyuu) and 1(Ichi), meanin Ni-jyuu-ichi.
In the same way you can read until 99.
For example, 44 = 4 x 10 + 4 (Yon-jyuu-yon) and 87 =8 x 10 + 7 (Hachi-jyuu-nana)
Did you get it?